Change Blindness

What are you paying attention to, and what are you missing?

Article No :466 | January 18, 2010 | by Michael Grossman

Depending on what we focus on, our brains can be completely blind to obvious changes going on around us. This is called "change blindness," and it is unnerving when you observe it. Below are a few examples of this in action.

This first video is an experiment conducted at Harvard where 75% of the people in the test don't notice that the man in front of them has turned into a different person. This was conducted in a formal test setting. The people involved were interviewed after the experiment to better understand their perception of events.

This next video shows change blindness being used as more of a parlor trick. Magician Derren Brown exploits this blind spot in a much more dramatic way. Changing clothes, race, and gender doesn't seem to matter to these people on the street. This demonstration isn't as controlled, but is a lot of fun to watch.

The last video is an "Awareness Test" that has been around for a while. You can run this test on yourself and on others.

The concept of change blindness highlights a potential problem for UX professionals. Most of the time, user researchers and UX architects begin their research with specific goals in mind, and are focused on a specific aspect of the product. But with this focus comes the risk that they will be blind to other aspects of the user's experience. What are we failing to capture when observing people using the products we design? We need to reserve space in our work for uncovering those things that we don't know we don't know, and make it an official part of the process. We will observe more of the moonwalking bears that teach us valuable lessons about our users and our products.

About the Author(s)

Michael merged his skills in graphic design and multimedia into a career in User Experience Design after graduating with a B.S. in Jazz in 1989. He has delivered projects for clients including ICAP, UBS, Kenneth Cole, Merrill Lynch, Apple, Time Warner, NFL Properties, AOL, Toshiba and W&R Grace. Visit his UX Blog, his website, or follow him on Twitter.

Didn't the original "You're on Candid Camera" program on US TV in the mid-1960s, hosted by Alan Funt (sp?) already demonstrate some of these so-called change blindness phenomena. I never see that program credited when I read CB articles. Does anybody else remember this?

I had received a notification that my Gmail app had updated on my phone. However, when it came time to send an email, I was paralyzed, as the "send" button had moved from bottom to an icon-only top-right. I was afraid to lose my email, and couldn't hover over the icon (thanks, touch-screen phone!) to learn the identity of the button. It even took me a solid minute to see that new button at all, as I was so used to seeing it on the bottom!

People get so used to doing things unconsciously, that a slight change can be jarring and unnerving.

The underlying issue: Focus. In the examples above, people were focused on signing a piece of paper or watching white shirts throwing a ball. If the man had handed back a pink piece of paper instead of the white one, I'm sure people would've noticed! When I'm focused on clicking send, and the send button is gone, I freak out! All the sudden, I'm slammed back to reality and relearning a system I knew by heart.

Nice post,
It does high-light a problem in attention awareness but as it pertains to change-blindness people who use or interact with something on a regular/daily basis will notice even the slightest differences.

But when we are doing usability testing this knowledge is immensely valuable.

I hadn't thought of the change-hyper-awareness other end of the spectrum. That is as important to UX design as it leads very often to design paralysis. Customers are so sensitive to change that you just never change. Great point.